In manufacturing, the handling of thin, fragile materials (herein referred to as “wafers”) can be very difficult due to the wastage, both of materials and of time, that can occur if the wafers are broken during the manufacturing process. Wafers may be of various materials, however, one particular example of a wafer is a silicon wafer such as that used in electronics, solar, and other applications.
Solar cell wafers are fragile, thin planar wafers that are typically made out of semiconductor materials such as silicon, GaAs, or the like. In order to increase efficiency and reduce material costs, solar cell wafers are being made thinner and thinner, causing many difficulties in the manufacturing process due to breakage and wastage of the solar cell wafers during handling.
One particular process in the manufacturing of solar cell wafers involves the wafers being loaded into and unloaded from a diffusion furnace for treatment. In this process, it is preferred that only one side of the solar cell wafer to be treated in the diffusion furnace. As such, the solar cell wafers are typically placed back to back (“BTB”) such that only one side of each wafer is presented to the environment of the diffusion furnace.
Conventional systems for handling wafers as they are moved into and out of the diffusion furnace tend to be quite complex and bulky and do not use floor space efficiently, including complex systems to accurately position the wafers in a back to back format. For example, some conventional systems use a complex comb structure in a carrier to attempt to accurately position the BTB wafers. The handling of wafers in this way can reduce throughput due to the amount of time required in handling and can still result in relatively large amounts of breakage and wastage of materials due to misalignment of wafers and the like.
As such, there is need for an improved system, apparatus and method of handling wafers and, in particular, for handling solar cell wafers.